side effects b12 injections weight loss for Non-Surgical B12 Injections & Weight Loss:

Other side effects that can occur include: Excessive sweat production Rapid weight gain Pain when breathing Shortness of breath when lying down Anxiety Increased or irregular heart rate Numbness, tingling or muscular weakness Increased thirst Urinary frequency B12 injections can also cause allergy symptoms immediately after administration, like difficulty breathing, a swollen throat, mouth, or swelling of the mouth, tongue or face

4) (Doddy et al., 1996

The drop from Low Transcobalamin to Zero Transcobalamin happened to me within the short time of just 1 month, at age 44

"One of the potential side effects of these medications is to delay gastric emptying, which has a unique risk or potential for aspiration for patients undergoing anesthesia